Various types of slip assemblies have been devised for securing a tool at a desired depth within a downhole tubular. Many such devices include multiple slips, slip arms, cages, and cones. Slip assemblies with dozens of downhole components are inherently a reliability concern. For example, slip segments may fall off a respective slip arm, causing failure of the downhole tool. Slip assemblies including numerous components may also cause local overstressing of the downhole casing or other tubular due to tolerance variation buildup, thereby causing casing failure due to the non-uniformity of distributing stresses over all the slip segments.
Reducing overstressing of a liner hanger body or a casing from a slip assembly in high axial load applications conventionally requires a sufficient slip area to handle the demanding loads. Increased loads may be the result of the longer and heavier liners, and their corresponding increased test pressures. To achieve additional slip area, additional slips and cones may be used, or the slip taper length may be made longer to achieve more slip area without adding system components.
U.S. Pat. No. 1,066,000 discloses slips for anchoring in a well. The well packer disclosed in U.S. Pat. Nos. 4,512,399 and 4,582,134 include slips and an expander with tapered expansion surfaces. U.S. Pat. No. 5,413,180 discloses a gravel packing service tool with slips. U.S. Pat. No. 5,906,240 discloses a c-ring slip having a passageway for installation of lines therethrough. U.S. Pat. No. 6,655,456 discloses a liner hanger assembly, and U.S. Pat. No. 6,761,221 discloses a liner hanger assembly with a c-ring slip body as shown in FIGS. 2A and 5. U.S. Pat. No. 6,739,398 discloses a linger hanger running tool with c-ring slips, as shown in FIGS. 1G, 2B, 8E, and 9A.
The disadvantages of the prior art are overcome by the present invention, and an improved slip assembly for securing a tool within a downhole tubular in a well is hereinafter disclosed.